This invention relates in general to the configuration of golf clubs and, more specifically, to golf club heads having progressive sizing, a slot or channel back to diagonally balance the club head and other features to aid a golfer in properly striking the ball.
A very wide variety of golf clubs have been designed over the years. Many different shaft and head materials have been used. Heads, both for blade-like "irons" and rounded head "woods" have a great many different configurations. Both "irons" and "woods" are often made from metal today.
As club design continues to improve, improved club aerodynamics through the swing becomes more important. Air flow distortions around the club head, hosel and shaft such as can occur due to turbulent air flow can reduce club head stability during a swing.
In the past, the heads of irons and woods have been made with opposite size progressions. Woods have heads that get smaller as the clubs get shorter. Irons, on the other hand, have had heads that become smaller as the clubs get longer. It was felt that in order to obtain uniform swing weights, the longer clubs must be the lightest. The easiest way to accomplish this was to reduce head size as the clubs became longer. However, the small head, longer clubs are the most difficult to hit correctly. Improving the ease of hitting the long irons would greatly improve an average golfer's game.
Optimizing club head balance is also of great importance. Early irons had flat backs or "muscle" backs. Today, these backs have been replaced by perimeter weighted or cavity backs. This is intended to increase the size of the "sweet spot", the area on the club face over which a correct shot can be hit. Such clubs still have difficulties with poor flight paths resulting twist when the ball is hit toward the heel or toe of the club face. The golf ball dispersion pattern on the face of a club (golf ball footprint over a number of shots) is always shaped like an egg that extends from the low heel to high toe. Increasing the size of the sweet spot and reducing this twist inducing tilt is very important to achieving consistently straight shots.
A "forgiving" club is one that will produce good shots even when the ball is hit off of the sweet spot center or its center of percussion and which will eliminate shot defects caused by head twist and energy losses in its inertia, and will produce consistent results.
Thus, there is a continuing need for improvements in golf clubs which reduce airflow turbulence during a swing, increase the sweet spot size and reduce the deleterious affects of twist, and improve the progression of club head size, apparent top line thickness and sole thickness to provide forgiving clubs, each of which is optimized for specific shots.